The purpose of the corners are to make it easier to erase particular lines
without accidentally erasing something else in the process.

I was lured to purchase this since I am a big fan of the 28-Corner Eraser
version. I use my planner as a scrapbook/sketch book and needed something
portable that doesn't collect dirt everywhere. I especially loved how the cap
has a strap attached to it as opposed to the Tombo Mono One where you can loose
the cap in an instant. However, this mini stick eraser is a bit too soft for my
taste. I would be erasing something and the eraser would bend increasing the
effort to erase a simple line. I love the concept and the cap for this
particular mini twist eraser, but the Tombo Mini One Twist eraser is the best so
far from my experience.

Definitely looks cool, and it is definitely well-built, but I just can't find
the functionality. Even though it has all these corners, the more I used it the
more it revealed to me that it was a gimmick. I prefer a Pink Pearl to it.